Clevis sensing lock

ABSTRACT

A latch mechanism includes a hook-handle assembly coupled to a first panel and a clevis coupled to a second panel. The hook-handle assembly engages the clevis to secure the first panel relative to the second panel.

PRIORITY CLAIM

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application Ser. No. 62/048,247, filed Sep. 9, 2014, whichis expressly incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to a latch for an aircraftengine nacelle, and more specifically to a locking mechanism for such alatch.

BACKGROUND

A variety of latches are used on aircraft to retain various componentsof the aircraft in a locked condition under circumstances such as flightand storage of the aircraft. During maintenance or repair periods thelatches must operate to unlock the corresponding panel, cowling or otherdevice from the aircraft. For example, upon a cowling the latch isdisengaged to allow the cowling to be operated away from the enginecomponents which it houses. The cowling, once opened, allows theaircraft maintenance professional to access the engine components. Atthe end of the repair event the cowling is closed. The latch is used tolock the cowling in the closed condition to retain the engine componentsin the housed condition.

As an additional matter, the maintenance professional may use a deviceto “clip” the latches closed to keep them from projecting out from theaircraft body or housing. The latches are clipped in a closed or lowerprofile position to prevent the latches from becoming bumped or frombumping the maintenance professional. Clipping the latches does notnecessarily close or lock the latch but allows the latch to bemaintained in a much lower profile against the aircraft housing or body.Since the latches are in a lower profile configuration, they reduce thechance of the maintenance professional bumping into them either with hisbody or with a piece of equipment. This can be useful to protect thelatches as well as the maintenance professional. However, clippedlatches can inadvertently appear to be locked and as such may fail to belocked. Additionally, even if the latches are operated to attempt tolock them a potential issue with the latch mechanism might interferewith complete locking and as such could inadvertently unlatch duringoperation. It would be desirable to develop a system and assembly to beused with a latch to help provide assurances that the latch will, infact, be closed and locked in the proper position.

This background information is provided to provide some informationbelieved by the applicant to be of possible relevance to the presentdisclosure. No admission is intended, nor is such an admission to beinferred or construed, that any of the preceding information constitutesprior art against the present disclosure. Other aims, objects,advantages and features of the disclosure will become more apparent uponreading of the following non-restrictive description of specificembodiments thereof, given by way of example only with reference to theaccompanying drawings.

SUMMARY

The present disclosure includes a clevis-sensing lock assembly for usewith a latching system. The clevis-sensing lock can be installed intothe latching system and provides structures which function to preventoperation of the clevis in the unlocked position. A device such as a keyor tool is used to unlock the latch and allow it to open. The structureand function of the clevis-sensing lock retains this device in the lockto prevent its removal unless the latch is in the fully closed position.Once in the fully closed position the lock can be closed and the deviceremoved. Additionally, an indicator or flag can be added to the deviceto further enhance the visibility of the locked or unlocked condition ofthe latch. The lock provides structures which function to interfere withthe operation of the clevis until the latch is in the desired closed andconfirmed locked position. The clevis-sensing lock can be used with aspecially designed latch or retrofitted to be used with a variety oflatches. The variety of latches can be remanufactured to provide thesame or substantially the same envelope of operation using virtually thesame components but replacing portions of the trigger assembly with thelock assembly.

According to the present disclosure, a latch mechanism includes ahook-handle assembly, a clevis, and a clevis-sensing lock. Thehook-handle assembly may include a hook member, a handle, and a linkagearrangement coupled between the hook member and handle. The clevis mayinclude a hook-end receiver and a coupler portion spaced apart from thehook-end receiver to at least partially define an opening therebetween.

In illustrative embodiments, the hook-end receiver may be configured toengage with a hook end of the hook member as the handle moves from anopen position extending away from the clevis toward a closed positionextending toward the clevis.

In illustrative embodiments, the clevis-sensing lock may be coupled tothe handle to move with the handle. The clevis-sensing lock may includea block, a lock cylinder received in the block and configured to rotaterelative to the block, and an interference member coupled to the lockcylinder to rotate with the lock cylinder relative to the block.

In illustrative embodiments, the interference member may be configuredto pass through the opening of the clevis and rotate relative to theblock to engage an underside of the clevis and the lock cylinder may beconfigured to control rotation of the interference member.

In illustrative embodiments, the latch mechanism may further include atumbler arrangement coupled between the lock cylinder and the block andconfigured to control rotation of the lock cylinder relative to theblock.

In illustrative embodiments, the tumbler arrangement may include adetent spring, a detent pin positioned between the lock cylinder and thedetent spring, and a tumbler pin positioned between the detent pin andthe lock cylinder. The detent spring may be configured to bias thedetent pin toward the tumbler pin. The detent pin may be configured toengage with the block and the lock cylinder to restrict rotation of thelock cylinder when an interface between the detent pin and the tumblerpin is misaligned from a lower surface of the lock cylinder.

In illustrative embodiments, the latch mechanism may further include akey configured to be received in the lock cylinder to engage with thetumbler pin and to align the interface between the detent pin and thetumbler pin with the lower surface of the lock cylinder.

In illustrative embodiments, the latch mechanism may further include akey having a head and a shaft coupled to the head. The shaft may beconfigured to be received in the lock cylinder to engage with thetumbler arrangement to allow rotation of the lock cylinder and the headmay be configured to extend away from the handle to provide anindication of an unlocked state of the clevis-sensing lock.

In illustrative embodiments, the key may further include a protrusionextending outward from the shaft and configured to engage with thehandle to trap the shaft within the lock cylinder when the lock cylinderis rotated relative to the block.

In illustrative embodiments, the lock cylinder may be formed to includean annular groove and an axial slot extending toward the interferencemember from the annular groove.

In illustrative embodiments, the latch mechanism may further include across-pin configured to slide in the annular groove and axial slot ofthe lock cylinder to control rotation of the lock cylinder.

In illustrative embodiments, the latch mechanism may further include theclevis may further include a fin extending from an upper surface clevisopposite the underside. The fin may be configured to move the cross-pinout of the axial slot and into the annular groove to allow rotation ofthe lock cylinder as the handle moves toward the closed position.

In illustrative embodiments, the lock cylinder may be formed to includea groove extending at least partially around a circumference of the lockcylinder. A fastener may extend through the handle and the block tocouple the clevis-sensing lock to the handle and may be received in thegroove of the lock cylinder.

In illustrative embodiments, the groove of the lock cylinder may beconfigured to limit rotation of the lock cylinder relative to the block.

According to the present disclosure, a method of operating a latchmechanism may include inserting a key into a clevis-sensing lock throughan aperture formed in a handle of a hook-handle assembly, rotating thekey to disengage an interference member of the clevis-sensing lock froma clevis, moving the handle relative to the clevis to disengage a fin ofthe clevis from the clevis-sensing lock to engage a cross-pin of theclevis-sensing lock with a lock cylinder of the clevis-sensing lock toblock rotation of the key such that the key is trapped in theclevis-sensing lock, and moving the handle to disengage a hook member ofthe hook-handle assembly from the clevis.

In illustrative embodiments, the method may further include moving thehandle toward the clevis to engage the hook member with the clevis,moving the handle toward the clevis to engage the fin with theclevis-sensing lock to disengage the cross-pin from the lock cylinder toallow rotation of the key, rotating the key such that the interferencemember is engaged with an underside of the clevis, and removing the keyfrom the clevis sensing lock.

In illustrative embodiments, inserting the key may include extending ashaft of the key into the lock cylinder and engaging a tumblerarrangement to allow rotation of the interference member.

In illustrative embodiments, removing the key may include removing theshaft from the lock cylinder and disengaging the tumbler arrangement toblock rotation of the interference member.

According to the present disclosure, a clevis-sensing lock may include ablock, a lock cylinder, a cross-pin, a tumbler arrangement, a couplershaft, and an interference member. The block may be formed to include acylinder-receiving bore extending into the block and a pin-receivingslot extending into the block to intersect with the cylinder-receivingbore. The lock cylinder may be configured to be received in thecylinder-receiving bore of the block and rotate relative to the block.The lock cylinder may include a first end and a second end spaced apartfrom the first end. The lock cylinder may be formed to include anannular groove, an axial slot extending toward the first end of the lockcylinder from the annular groove, and a key-receiving bore extendingfrom the second end toward the first end.

In illustrative embodiments, the cross-pin may be positioned within thepin-receiving slot of the block and configured to slide in the annulargroove and axial slot of the lock cylinder to control rotation of thelock cylinder.

In illustrative embodiments, the tumbler arrangement may be coupledbetween the lock cylinder and the block and configured to controlrotation of the lock cylinder.

In illustrative embodiments, the coupler shaft may be positioned withinthe key-receiving bore and coupled with the lock cylinder to rotatetherewith.

In illustrative embodiments, the interference member may be coupled tothe coupler shaft at the first end of the lock cylinder to rotate withthe lock cylinder.

In illustrative embodiments, the clevis-sensing lock may further includea guide pin having a head and a hole extending through the head. Theblock may be formed to include a cavity configured to receive the guidepin. The cross-pin may extend through the hole of the guide pin.

In illustrative embodiments, the tumbler arrangement may include adetent spring, a detent pin positioned between the lock cylinder and thedetent spring, and a tumbler pin positioned between the detent pin andthe lock cylinder. The detent spring may be configured to bias thedetent pin toward the tumbler pin. The detent pin may be configured toengage with the block and the lock cylinder to restrict rotation of thelock cylinder when an interface between the detent pin and the tumblerpin is misaligned from a lower surface of the lock cylinder.

In illustrative embodiments, the clevis-sensing lock may further includea fastener extending through the block. The lock cylinder may be formedto include a groove extending at least partially around a circumferenceof the lock cylinder. The fastener may be received in the groove of thelock cylinder. The groove of the lock cylinder may be configured tolimit rotation of the lock cylinder relative to the block.

Other aims, objects, advantages and features of the disclosure willbecome more apparent upon reading of the following non-restrictivedescription of specific embodiments thereof, given by way of exampleonly with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be described hereafter with reference to theattached drawings which are given as a non-limiting example only, inwhich:

FIG. 1 is a perspective view of an aircraft engine assembly showing thatthe engine assembly includes a nacelle or fan cowl surrounding a gasturbine engine supported on an aircraft by an engine-mounting bracketand suggesting that the fan cowl incorporates a latch mechanism inaccordance with the present disclosure having a flag to indicate to anoperator when the latch mechanism is in an unlocked state;

FIG. 2 is a perspective view of the latch mechanism of FIG. 1 showingthe latch mechanism in an unlocked and open state and suggesting that ahook member is spaced apart from a clevis to allow panels of the fancowl to be moved from a closed position to an open position;

FIG. 3 is a lower perspective view of the latch mechanism of FIG. 2showing the latch mechanism in a locked and closed state and suggestingthat a clevis-sensing lock extends through the clevis and engages withflats on an underside of the clevis;

FIG. 4 is an upper perspective view of the latch mechanism of FIG. 3showing the latch mechanism in the locked and closed state andsuggesting that the clevis-sensing lock retains the latch mechanism inthe locked and closed state to prevent inadvertent opening of the latchmechanism;

FIG. 5 is an exploded perspective view of the latch mechanism of FIG. 2showing that the clevis-sensing lock includes a block, a lock cylinder,and an interference member coupled to the lock cylinder and suggestingthat a tumbler pin arrangement regulates movement of the lock cylinder;

FIG. 6 is a perspective view of the latch mechanism of FIG. 4 showing akey having the flag attached thereto positioned for insertion into thelatch mechanism to engage with the clevis-sensing lock;

FIG. 7 is a view similar to FIG. 6 showing the key inserted into to theclevis-sensing lock and suggesting that the keys is rotated to place thelatch mechanism into an unlocked and closed position to allow a user toopen the latch mechanism;

FIG. 8 is a lower perspective view of the latch mechanism of FIG. 7showing that protruding ends of the interference member engages with theflats on a narrowed portion of the clevis prior to rotation of the key;

FIG. 9 is a view similar to FIG. 8 showing the interference memberrotated with the key such that flats of the interference member isaligned with the narrowed portion to allow the interference member topass out through an opening of the clevis;

FIG. 10 is an enlarged perspective view of a hook latch assembly of thelatch mechanism of FIG. 2 and showing that the clevis-sensing lock iscoupled to an underside surface of a handle of the hook latch assembly;

FIG. 11 is an enlarged view of the clevis-sensing lock of FIG. 10showing that the lock cylinder extends into the block and a couplershaft extends through the lock cylinder and interference member tocouple the interference member with the lock cylinder to rotatetherewith;

FIG. 12 is a perspective view of the latch mechanism of FIG. 6 showingthe key partially inserted into the clevis-sensing lock;

FIG. 13 is a partial sectional view taken along line 13-13 in FIG. 12showing the key extending into the clevis-sensing lock toward thetumbler pin arrangement and suggesting that the tumbler pin arrangementblocks rotation of the lock cylinder when misaligned from a bottom planeof the lock cylinder;

FIG. 14 is a view similar to FIG. 13 showing the key fully inserted intothe lock cylinder such that a protrusion of the key engages a shoulderof the lock cylinder such that the tumbler pin arrangement is alignedwith the bottom plane of the lock cylinder;

FIG. 15 is a perspective view of the hook latch assembly of FIG. 14showing the key rotated relative to the handle;

FIG. 16 is a top plan view of the handle of FIG. 15 showing that theprotrusion of the key is positioned under the handle to trap the key inthe locking mechanism, and suggesting that the key can only be removedwhen rotated to align with a key hole of the handle;

FIG. 17 is a perspective view of the block of FIG. 15 showing a fastenerextending through the block for connecting the block to the handle andsuggesting that the fastener rides in a groove of the lock cylinder;

FIG. 18 is a partial sectional view taken along line 18-18 in FIG. 17showing that the fastener engages with the lock cylinder to preventover-rotation of the lock cylinder;

FIG. 19 is a perspective view of the lock cylinder of FIG. 15 showingthat cross-pins slide in a groove of the lock cylinder and are retainedby heads of guide pins and suggesting that the lock cylinder is about torotate relative to the cross-pins;

FIG. 20 is a view similar to FIG. 19 showing the cross-pins locatedabove slots formed in the lock cylinder after rotation of the lockcylinder and suggesting that springs are positioned to force thecross-pins downward;

FIG. 21 is a view similar to FIG. 20 showing the cross-pins positionedin the slots of the lock cylinder and suggesting that the cross-pinsprevent rotation of the cylinder while located in the slots;

FIG. 22 is a side elevation view of the latch mechanism of FIG. 7showing the key inserted into the clevis-sensing lock and suggestingthat a handle release is rotated to allow the handle to be liftedrelative to the clevis;

FIG. 23 is a view similar to FIG. 22 showing the handle partially liftedto pass the clevis-sensing lock out of the clevis;

FIG. 24 is a view similar to FIG. 23 showing the handle rotated relativeto the clevis it release the hook member from the clevis;

FIG. 25 is a side elevation view of the latch mechanism of FIG. 7showing the clevis rotated such that fins coupled to an upper surfaceare pointing downward and suggesting that the key cannot be rotated orremoved while the clevis is in this position;

FIG. 26 is an enlarged view of the latch mechanism of FIG. 25 showingthe clevis rotated such that the fins point upwards and suggesting thatas the handle is lowered toward the clevis the fins engage with theheads of the guide pins;

FIG. 27 is a view similar to FIG. 26 showing the handle fully loweredand suggesting that the fins of the clevis force the cross-pins upwardout of the slot of the lock cylinder to allow rotation and removal ofthe key;

FIG. 28 is a perspective view of a hook latch assembly incorporating analternate embodiment of a clevis-sensing lock in accordance with thepresent disclosure;

FIG. 29 is an upper perspective view of the hook latch assembly of FIG.28;

FIG. 30 is an exploded assembly view of the hook latch assembly of FIG.28;

FIG. 31 is a perspective view of the alternative clevis-sensing lock ofFIG. 28;

FIG. 32 is a perspective view of the alternative clevis-sensing lock ofFIG. 31;

FIG. 33 is a view similar to FIG. 32;

FIG. 34 is a sectional view taken along line 34-34 in FIG. 32;

FIG. 35 is a view similar to FIG. 34;

FIG. 35 is a perspective view of a key used with the alternativeclevis-sensing lock of FIG. 31;

FIG. 37 is a perspective view of a key interface of the alternativeclevis-sensing lock of FIG. 31;

FIG. 38 is a sectional view taken along line 38-38 in FIG. 35;

FIG. 39 is a view similar to FIG. 34; and

FIG. 40 is an upper perspective view of the alternative clevis-sensinglock of FIG. 31.

The exemplification set out herein illustrates embodiments of thedisclosure that are not to be construed as limiting the scope of thedisclosure in any manner. Additional features of the present disclosurewill become apparent to those skilled in the art upon consideration ofthe following detailed description of illustrative embodimentsexemplifying the best mode of carrying out the disclosure as presentlyperceived.

DETAILED DESCRIPTION

While the present disclosure may be susceptible to embodiment indifferent forms, there is shown in the drawings, and herein will bedescribed in detail, embodiments with the understanding that the presentdescription is to be considered an exemplification of the principles ofthe disclosure. The disclosure is not limited in its application to thedetails of structure, function, construction, or the arrangement ofcomponents set forth in the following description or illustrated in thedrawings. The disclosure is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as limiting. The useof various phrases and terms is meant to encompass the items orfunctions identified and equivalents thereof as well as additional itemsor functions. Unless limited otherwise, various phrases, terms, andvariations thereof herein are used broadly and encompass all variationsof such phrases and terms. Furthermore, and as described in subsequentparagraphs, the specific configurations illustrated in the drawings areintended to exemplify embodiments of the disclosure. However, otheralternative structures, functions, and configurations are possible whichare considered to be within the teachings of the present disclosure.Furthermore, unless otherwise indicated, the term “or” is to beconsidered inclusive.

The foregoing terms as well as other terms should be broadly interpretedthroughout this application to include all known as well as allhereafter discovered versions, equivalents, variations and other formsof the abovementioned terms as well as other terms. The presentdisclosure is intended to be broadly interpreted and not limited.

An engine assembly 10 for attachment with an aircraft is shown inFIG. 1. Engine assembly 10 includes a nacelle or fan cowl 12 positionedto surround a gas turbine engine 14 supported by an engine-mountingbracket 16 for securing engine assembly 10 to the aircraft. Nacelle 12includes a right-side panel 13 and a left-side panel 15 which aremovable relative to engine 14 between a closed position, shown in FIG.1, and an open position extending away from engine 14.

A latch mechanism 30 is coupled between panels 13, 15 to secure panels13, 15 in the closed position at the selection of a user as suggested inFIG. 1. One of the problems that can occur with such a latch mechanismis that the latch mechanism can be mislocked. In this regard, the latchmechanism can be closed under some circumstances and appear to be lockedto the maintenance professional, when, in fact, it may not be fullyengaged or fully locked. It is important to return the aircraftcomponents, such as panels, doors, and cowlings, to the appropriatein-flight condition to seal and house the portions of the aircraft. Itis also important to maintain the latch mechanism to retain thesecomponents in the closed locked condition. As such, it is important toprovide a system to assure that the latch mechanism is, in fact, in theappropriate condition when locked.

As such, latch mechanism 30 includes a hook-handle assembly 32 coupledto one of panels 13, 15 and a clevis 34 coupled to the other of panels13, 15 as suggested in FIG. 2. A clevis-sensing lock 50 in accordancewith the present disclosure is coupled to hook-handle assembly 32 and isconfigured to pass through and engage with clevis 34 to maintain latchmechanism 30 in a locked and closed position as suggested in FIGS. 3 and4. It should be noted, that clevis-sensing lock 50 can be configured foruse with a variety of latch mechanisms.

A key 80 is inserted into clevis-sensing lock 50 to unlock latchmechanism 30 as suggested in FIGS. 2 and 6-9. In the illustrativeembodiment, a signal flag 17 is coupled to key 80 to indicate to anoperator or user that latch mechanism 30 is unlocked as suggested inFIGS. 1 and 2. An enlarged head 84 of key 80 also provides such anindication if signal flag 17 is lost or removed inadvertently. Signalflag 17 and key 80 allow a user to inspect engine assembly 10 to ensurethat latch mechanisms 30 are locked and closed to secure panels 13, 15in the closed position. For example, if no signal flag 17 or key 80 arevisible, then there is an indication that latch mechanisms 30 are in thelocked and closed position as suggested in FIG. 4.

Hook-handle assembly 32 includes a handle 42 used to operate latchmechanism 30, a hook member 40, and a linkage arrangement 44 coupledbetween handle 42 and hook member 40 as suggested in FIGS. 2 and 5.Latch mechanism 30 is coupled to one of panels 13, 15 by inserting a pinthrough a sleeve 36 of linkage arrangement 44. Hook-handle assembly 32moves relative to the pin inserted through sleeve 36 between theunlocked and open position, shown in FIG. 2, and the locked and closedposition, shown in FIG. 4, and as suggested in FIGS. 22-24.

Clevis 34 includes a hook-end receiver 62 for engaging with a hook end60 of hook member 40 and a coupler portion 140 coupled to a clevisretainer 38 as suggested in FIG. 2. In the illustrative embodiment,coupler portion 140 is threaded. Clevis retainer 38 couples with theother of panels 13, 15 opposite hook-handle assembly 32 and isconfigured to allow axial adjustment of clevis 34 by engaging withcoupler portion 140. Handle 42 is rotated toward clevis 34 to engagehook end 60 with hook-end receiver 62 and pass an interference member 56of clevis-sensing lock 50 through an opening 52 of clevis 34, andinterference member 56 is rotated by key 80 to engage with flats 106 onan underside 58 of clevis 34 to secure panels 13, 15 in the closedpositon so that key 80 can be removed as suggested in FIGS. 2-4. Clevis34 also includes fins 72 positioned on an upper surface 74 to engagewith clevis-sensing lock 50 to allow rotation and removal of key 80 assuggested in FIGS. 25-27.

Clevis-sensing lock 50 includes a block 64 coupled to an undersidesurface 116 of handle 42 and a coupler shaft 68 configured to coupleinterference member 56 with block 64 as suggested in FIGS. 2 and 10-11.Block 64 is coupled to handle 42 by pins 70 and is configured to receivea tumbler assembly 66 to control rotation of interference member 56 assuggested in FIG. 5. In some embodiments, pins 70 are in the form of aremovable fastener or in the form of a rivet-type fastener. A lockcylinder 102 of tumbler assembly 66 is received in a bore 154 of block64 and coupled to coupler shaft 68 to rotate with interference member 56as suggested in FIG. 5. A tumbler pin arrangement 120 of tumblerassembly 66 is positioned between lock cylinder 102 and block 64 tocontrol movement of lock cylinder 102 as suggested in FIGS. 5 and 12-14.Lock cylinder 102 is formed to include a bore 92 configured to receive ashaft 98 of key 80 for rotation of lock cylinder 102 and interferencemember 56 as suggested in FIGS. 5 and 15-18.

To assemble clevis-sensing lock 50, coupler shaft 68 is positionedwithin bore 92 of lock cylinder 102, and a pin 100 is engaged with holes103, 105 of coupler lock cylinder 102 and coupler shaft 68,respectively, as suggested in FIG. 5. Tumbler pin arrangement 120includes detent pins 130, detent springs 132, and discrete lengthtumbler pins 122. In the illustrative embodiment, four of each of detentsprings 132, detent pins 130, and tumbler pins 122 are shown. In someembodiments, more or less of each of detent springs 132, detent pins130, and tumbler pins 122 are used. The unique arrangement of tumblerpins 122 between various latch mechanisms 30 provides a degree ofselectivity to allow only certain keys 80 to work with eachclevis-sensing lock 50, thus providing a general security keyingfeature. While a uniform key could be used across all latchingplatforms, the additional security may enhance the use of theclevis-sensing lock 50 to provide security features as well as the abovedescribed and herein described benefits.

Tumbler pins 122 are inserted into corresponding bores within lockcylinder 102 and lock cylinder 102 is inserted into bore 154 of block 64as suggested in FIG. 5. Detent pins 130 are inserted into block 64 toengage with tumbler pins 122 and detent springs 132 are inserted intoblock 64 to engage with detent pins 130. A retainer plate 134 is engagedwith an underside of block 64 to retain tumbler pin arrangement 120within block 64. Coupler shaft 68 is inserted though interference member56 and is coupled to coupler shaft 68 by a pin 104 extending throughholes 107, 109 of interference member 56 and coupler shaft 68,respectively.

Guide pins 110 are received in cavities 76 of block 64 as suggested inFIG. 5. Guide pins 110 include a head 182 and shaft 111 coupled to head182. A spring 112 is positioned to surround shaft 111. Head 182 isformed to include a hole 190 for receiving a cross-pin 114. Guide pins110 and springs 112 are inserted into cavities 76 and cross-pins 114 areinserted through slots 192 formed in block 64 and holes 190 of heads 182to retain guide pins 110 within cavities 76. Block 64 is coupled tohandle 42 by pins 70 such that an upper portion of cavities 76 and sideportions of slots 192 are covered. As such, handle 42 retains springs112 within cavities 76 and cross-pins 114 within slots 192.

Interference member 56 includes protruding portions 150 and flats 142extending between protruding portions 150 as shown in FIG. 8. Protrudingportions 150 are configured to engage with flats 106 of a narrowedportion 146 of clevis 34 to lock latch mechanism 30. Key 80 is insertedthrough an aperture 82 in handle 42 to engage with clevis-sensing lock50 as suggested in FIG. 6. Key 80 is then rotated to rotate interferencemember 56 and align flats 142 with narrowed portion 146 such thatprotruding portions 150 are disengaged from flats 106 and interferencemember 56 is allowed to pass through opening 52 of clevis 34 assuggested in FIGS. 7-9.

Clevis-sensing lock 50, as assembled, is shown in FIGS. 10 and 11.Coupler shaft 68 and lock cylinder 102 are aligned with aperture 82 ofhandle 42 to allow insertion of key 80 as suggested in FIG. 10. Detentpins 130 are positioned to engage with lock cylinder 102 to blockrotation of lock cylinder 102 until key 80 is inserted as suggested inFIG. 11. In the illustrative embodiment, clevis-sensing lock 50 wasassembled and attached to handle 42 such that clevis-sensing lock 50 isinitially in the locked orientation as suggested in FIGS. 10 and 11.After key 80 is inserted and turned for the first time, clevis-sensinglock 50 will need to be engaged with clevis 34 in order to turn andremove key 80 as further detailed below.

Key 80 includes head 84 and shaft 98 coupled to head 84 as shown in FIG.5. Shaft 98 is hollow to define a cavity 96 sized to receive couplershaft 68. Lock cylinder 102 is formed to define a shoulder 101 as shownin FIG. 17. A protrusion 94 extends radially from shaft 98 and aperture82 of handle 42 is shaped to allow shaft 98 and protrusion 94 to passtherethrough as suggested in FIG. 12.

In the locked orientation, an interface between tumbler pins 122 anddetent pins 130 is misaligned from a bottom plane P of lock cylinder 102such that detent pins 30 engage with lock cylinder 102 and block 64 toprevent rotation of lock cylinder 102 as suggested in FIG. 13. A leadingend 90 of key 80, having mating portions 124 corresponding to tumblerpins 122, extends into lock cylinder 102 to engage with tumbler pins 122and align detent pins 130 with bottom plane P to allow rotation of lockcylinder 102 as suggested in FIGS. 13 and 14. Protrusion 94 of key 80engages with shoulder 101 of lock cylinder 102 to limit insertion of key80 and ensure proper alignment of detent pins 130 with bottom plane P.

As key 80 is rotated to unlock clevis-sensing lock 50, protrusion 94extends under handle 42 and becomes misaligned from aperture 82 assuggested in FIGS. 15 and 16. As such, key 80 is trapped insideclevis-sensing lock 50 until key 80 is turned to re-lock clevis-sensinglock 50. This prevents key 80 and signal flag 17 from being removedbefore latch mechanism 30 is in the locked and closed position to ensurethat panels 13, 15 are properly secured in the closed position.

Lock cylinder 102 is formed to include a groove 170 as shown in FIGS. 17and 18. One of pins 70 extends through block 64 to engage with groove170. Groove 170 only partially extends around lock cylinder 102 tocontrol rotation of lock cylinder 102. In the illustrative embodiment,lock cylinder 102 is limited to about 90 degrees of rotation. In someembodiments, that lock cylinder 102 rotates further than 90 degrees.Lock cylinder 102 is also formed to include an annular groove 158 withaxial slots 180 extending downward therefrom as shown in FIGS. 19-21.Cross-pins 114 slide in annular groove 158 as lock cylinder 102 isrotated as suggested in FIGS. 19-20. Lock cylinder 102 is rotated untilcross-pins 114 are aligned with axial slots 180. Cross-pins 114 areforced into axial slots 180 by springs 112 to engage with lock cylinder102 and block rotation of lock cylinder 102 as suggested in FIGS. 20-21.

Once clevis-sensing lock 50 is unlocked by key 80, latch mechanism 30can be opened as suggested in FIGS. 22-24. A handle release 46 iscoupled to handle 42 and engages with hook member 40 when latchmechanism 30 is in a closed position as suggested in FIG. 22. Handlerelease 46 is rotated to disengage from hook member 40. Handle 42 islifted to pass interference member 56 out of clevis 34 as suggested inFIG. 23. Further rotation of handle 42 disengages hook end 60 fromhook-end receiver 62 to allow movement of hook-handle assembly 32relative to clevis 34 as suggested in FIG. 24.

Fins 72 of clevis 34 are engage with guide pins 110 to allow rotationand removal of key 80 as suggested in FIGS. 25-27. Clevis 34 is shownwith fins 72 facing downward in FIG. 25. As such, even though latchmechanism 30 is in a closed position, removal of key 80 is prevented byclevis-sensing lock 50. Thus, latch mechanism 30 is prevented from beingin an improper unlocked and closed position where panels 13, 15 mayinadvertently open during operation of the aircraft. With clevis 34properly oriented, fins 72 engage with guide pins 110 during closure oflatch mechanism 30 to move cross-pins 114 out of axial slots 180 andallow rotation of lock cylinder 102 as suggested in FIGS. 26-27.

A hook-handle assembly 32 a incorporating an alternative clevis-sensinglock 50 a in accordance with the present disclosure is shown in FIG. 28.Similar to hook-handle assembly 32, hook-handle assembly 32 a includes ahandle 42 a, a hook member 40 a, and a linkage arrangement 44 a coupledbetween handle 42 a and hook member 40 a. A handle release 46 a iscoupled to handle 42 a to engage with hook member 40 a. Clevis-sensinglock 50 a is coupled to an underside surface 116 a of handle 42 a. Inthe illustrative embodiment, hook-handle assembly 32 a andclevis-sensing lock 50 a are configured to cooperate with the sameclevis 34 as hook-handle assembly 32 of latch mechanism 30, describedabove. Hook-handle assembly 32 a also operates in a similar fashion tohook-handle assembly 32. As such, discussion of hook-handle assembly 32a will be limited for sake of brevity. As discussed herein, features ofhook-handle assembly 32 can be incorporated into hook-handle assembly 32a, and vice versa, without departing from the present disclosure.

Clevis-sensing lock 50 a includes a block 64 a and a lock cylinder 102 aconfigured to couple an interference member 56 a with block 64 a assuggested in FIGS. 28 and 30. Block 64 a is coupled to handle 42 a bypins 70 a and is configured to receive a key interface 68 a to controlrotation of interference member 56 a coupled to lock cylinder 102 a assuggested in FIG. 30. Lock cylinder 102 a is received in a bore 154 a ofblock 64 a and coupled to key interface 68 a by a pin assembly 104 a torotate with interference member 56 a. Pin assembly 104 a moves relativeto a notch 184 a of block 64 a to control movement of lock cylinder 102a as suggested in FIGS. 32-35.

Lock cylinder 102 a is formed to include a bore 92 a aligned with anaperture 82 a of handle 42 a and configured to receive a shaft 98 a of akey 80 a for rotation of lock cylinder 102 a and interference member 56a as suggested in FIGS. 29 and 30. Key 80 a includes a head 84 a coupledto shaft 98 a. Shaft 98 a is formed to define a flat side 97 a to orientkey 80 a during insertion. Key 80 a also includes a grip tip 91 acoupled to shaft 98 a and configured to engage with key interface 68 aas suggested in FIGS. 30 and 36-37.

To assemble clevis-sensing lock 50 a, a tamper guard 186 a, keyinterface 68 a, a spring 136 a, and a spacer 188 a are inserted intolock cylinder 102 a and retained therein by a retainer ring 189 a assuggested in FIG. 30. A pin 113 a is inserted through a slot 107 a oflock cylinder 102 a and a hole 109 a of key interface 68 a. Pin 113 a issecured by a sleeve 115 a coupled to pin 113 a to form pin assembly 104a. Spring 136 a engages with spacer 188 a to bias key interface 68 a andpin assembly 104 a toward an upper end of slot 107 a.

Guide pins 110 a are received in cavities 76 a of block 64 a assuggested in FIG. 30. Guide pins 110 a include a head 182 a and shaft111 a coupled to head 182 a. A spring 112 a is positioned to surroundshaft 111 a. Head 182 a is formed to include a hole 190 a for receivinga cross-pin 114 a. Guide pins 110 a and springs 112 a are inserted intocavities 76 a and cross-pins 114 a are inserted through slots 192 aformed in block 64 a and holes 190 a of heads 182 a to retain guide pins110 a within cavities 76 a. Lock cylinder 102 a is inserted into a bore154 a of block 64 a and engaged by cross-pins 114 a.

A ball detent assembly 172 a is positioned within a ball detent receiver178 a as suggested in FIG. 30. Ball detent assembly 172 a includes aspring 174 a and a ball bearing 176 a. Spring 174 a is configured tobias ball bearing 176 a toward a detent recess 179 a of lock cylinder102 a as suggested in FIG. 40. Block 64 a is coupled to handle 42 a bypins 70 a such that an upper portion of cavities 76 a and ball detentreceiver 178 a, and side portions of slots 192 a, are covered assuggested in FIG. 30. As such, handle 42 a retains springs 112 a withincavities 76 a, ball detent assembly 172 a within ball detent receiver178 a, and cross-pins 114 a within slots 192 a.

Similar to interference member 56, interference member 56 a includesprotruding portions 150 a and flats 142 a extending between protrudingportions 150 a as shown in FIG. 30. Protruding portions 150 a areconfigured to engage with clevis 34. Flats 142 a are configured to alignwith clevis 34 such that protruding portions 150 a are disengaged fromclevis 34 and interference member 56 a is allowed to pass throughopening 52 of clevis 34.

Clevis-sensing lock 50 a, as assembled, is shown in FIG. 31. In theillustrative embodiment, clevis-sensing lock 50 a was assembled andattached to handle 42 a such that clevis-sensing lock 50 a is initiallyin a locked orientation. After key 80 is inserted and turned for thefirst time, clevis-sensing lock 50 will need to be engaged with clevis34 in order to turn and remove key 80 a as further detailed below.

Key 80 a is inserted into clevis-sensing lock 50 a to move pin assembly104 a out of notch 184 a as suggested in FIGS. 32 and 33. Shaft 98 a ofkey 80 a extends into lock cylinder 102 a and grip tip 91 a passesthrough tamper guard 186 a to engage with key interface 68 a assuggested in FIG. 34. Key 80 a is forced downward against the force ofspring 136 a to move pin assembly 104 a as suggested in FIG. 35. In theillustrative embodiment, grip tip 91 a has a geometric shape, such as atriangle, which corresponds with a geometric shape of a tip receiver 69a of key interface 68 a as suggested in FIGS. 36 and 37. Key interface68 a also includes a projecting portion 67 a to engage with lockcylinder 102 a. As such, grip tip 91 a engages with tip receiver 69 a torotate key interface 68 a, which in turn engages with lock cylinder 102a to rotate lock cylinder 102 a with key 80 a.

Shaft 98 a of key 80 a is formed to include a groove 95 a as suggestedin FIGS. 35-36 and 38. Side 97 a of shaft 98 a allows key 80 a to passby pin 70 and into lock cylinder 102 a as suggested in FIG. 35. Key 80 ais allowed to turn to unlock clevis-sensing lock 50 a when groove 95 aaligns with pin 70 a as suggested in FIGS. 35 and 38. Lock cylinder 102a also includes a groove 170 a which cooperates with pin 70 a torestrict rotation of lock cylinder 102 a. Cross-pins 114 a cooperatewith a groove 158 a and slot 180 a of lock cylinder 102 a to furthercontrol rotation of lock cylinder 102 a, as suggested in FIGS. 30 and31, similar to clevis-sensing lock 50, described above.

Clevis-sensing lock 50 a includes anti-tamper features as suggested inFIGS. 39 and 40. Tamper guard 186 a minimizes the ability of a lock pick99 a, such as a screw driver or other tool, to enter clevis-sensing lock50 a and rotate lock cylinder 102 a as suggested in FIG. 39. Tamperguard 186 a is configured to slide and rotate on key interface 68 awithout providing sufficient friction to turn lock cylinder 102 a todisengage interference member 56 a from clevis 34. Ball detent assembly172 a engages with lock cylinder 102 a to increase the force required toturn lock cylinder 102 a as suggested in FIG. 40. These featurescooperate to prevent unlocking of clevis-sensing lock 50 a without theuse of key 80 a.

In illustrative embodiments, the clevis-sensing locks described hereincan be configured for use with a specific latch design or configured tobe used as a retrofit on a remanufactured latch. An existing latchassembly can reuse most of the parts with perhaps a modification to thehandle to remove a pre-existing handle release and to accommodate aclevis-sensing lock. Additionally, the clevis can be replaced merely bydisengaging the threaded portion of the old clevis and attaching a newclevis which will include the fins and other corresponding structuresdetailed above. This design is easy to operate, difficult to defeat, andprovides a nearly fail-proof method of ensuring the latch has properlysecured the latch cowl.

In illustrative embodiments, a clevis-sensing lock can be retained on alatch mechanism for preventing the latch mechanism from openinginadvertently. The clevis-sensing lock includes a tool, key, or otherdevice which must be used to unlock the clevis-sensing lock to permitmovement of the handle to disengage the latch mechanism. The key cannotbe removed from the lock when the latch is open. Furthermore, the keyincludes a visual indicator such as a flag, streamer, or other devicewhich provides a clear visual indicator that the key is retained in thelock. This visual indicator extends away from the aircraft to provide aclear visual indication of the unlatched condition. Since the key canonly be removed from the lock when the latch is, in fact, in a properclosed position, the presence of such a visual indicator indicates thatthe latches are not secure for flight operations.

Engine cowls may sometimes appear to be in a latched closed positionwhen they are not due to the low profile of the latches and low heightfrom the ground of the engines of the aircraft. It is often times thattechnicians will clip the latches up tight against the cowling withoutlatching them to prevent snags with clothing during operations on theengine. These situations can be problematic if an aircraft takes offwhile the latches are open, and may cause damage to the cowlings orengines while in flight.

In illustrative embodiments, a clevis sensing lock can be attached toany hook latch that engages with a clevis. The clevis sensing lockattaches to the handle of the hook latch, and passes through the cleviswhen the latch is closed. It requires a key or tool to unlock the latchand allow the latch to open. When the latch is open, the key cannot beremoved from the handle. They key has a long flag or streamer attachedto it so that anybody standing around the aircraft, not necessarily nearthe engine, can see that the cowls are not closed and latched. Tounlatch the cowls, the operator inserts the key, with the long flag orstreamer attached, into the latch, turns the key, then opens the latch.

In illustrative embodiments, the lock includes a block which holds allof the lock's internal parts to the handle of the hook latch. The blockhas a large hole for a lock cylinder, and some slots and holes for somepins, guides, and springs. Another pair of slots on the block allowsfins that are attached to the clevis to fit into the block. The T-shapedlock cylinder, which fits into the block, has two large flats on oneend, which allows it to fit through the clevis during handle opening andclosing.

In illustrative embodiments, at the other end of the lock, there is ahole for a key to fit into. Near the open end of the hole, the lockcylinder has a retaining groove that protrudes into the hole, but onlypart way around the lock cylinder. This groove on the lock cylinderengages with a rivet that passes through the handle and through theblock in such a way that the lock cylinder cannot come out of the lock,and in such a way that the lock cylinder can only turn a predeterminedamount. The rivet protrudes into the hole of the lock such that the keyhas a corresponding flat on it that allows the key to pass by the rivetwhen the latch is closed. When the key is inserted into the lock, agroove on the key matches the groove on the lock cylinder that engageswith the rivet that holds the lock cylinder in place. When the key isturned, the groove on the key engages with the rivet, which prevents thekey from being removed.

In illustrative embodiments, the end of the key has a feature whichgrabs onto a mating component, sometimes called a plug, down in thebottom of the hole of the lock cylinder. The shape at the end of the keycan be any shape that allows the key to grab the plug and turn it. Theplug has a spring behind it, and a hole for a cross pin, which fits intoa through slot on the lock cylinder. The cross pin limits the amount ofaxial movement in the lock cylinder and also ensures that the key, plug,and lock cylinder turn together. When the key is not inserted into thelock, the cross pin is pushed by the spring, via the plug, into aV-groove on the block, thereby preventing accidental rotation of thelock cylinder when the latch is closed. When the key is inserted intothe lock, the cross pin is pushed out of the V-groove on the block, andthe cylinder is allowed to turn. With this arrangement of the key, lockcylinder, and plug, they cannot be turned unless the key is fullyinserted into the lock cylinder and engaged with the plug.

In illustrative embodiments, the lock cylinder also has a circulargroove and two intersecting straight slots, which are parallel to theaxis of the lock cylinder, that allow the ends of two locking pins totravel in them. The locking pins ride in a guide, inside the block. Eachguide is pushed by a spring toward the clevis. The clevis has two finswhich, in the latch closed position, engage with the guides, and pushthe guides and locking pins into the circular groove. When the lockingpins are in the circular groove, the lock may be turned toward theunlock position. Once the lock cylinder is turned completely to theunlock position, the handle may be moved in the direction that opens thelatch, and the engaging portion of the lock may pass through the clevis.The clevis has two fins which fit into some blind slots on the block,and push the guides and locking pins when the latch is closed. As thelatch opens, and the handle moves away from the clevis, the fins on theclevis disengage from the guides and locking pins. The locking pins arethen pushed down into the straight slots on the lock cylinder, whichprevents the lock cylinder from turning toward the lock position andprevents the key from being removed.

In illustrative embodiments, there could be one or two flats on opposingsides of the lock cylinder. The locking pins would be longer and offsetfrom the axis of the cylinder, such that they would fit tangentiallyinto the circular groove on lock cylinder when the latch is in theclosed position. When the latch is open, the locking pins would slidedown onto the flats of the lock cylinder and prevent the lock cylinderfrom turning.

While the present disclosure describes various exemplary embodiments,the disclosure is not so limited. To the contrary, the disclosure isintended to cover various modifications, uses, adaptations, andequivalent arrangements based on the principles disclosed. Further, thisapplication is intended to cover such departures from the presentdisclosure as come within at least the known or customary practicewithin the art to which it pertains. It is envisioned that those skilledin the art may devise various modifications and equivalent structuresand functions without departing from the spirit and scope of thedisclosure as recited in the following claims. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

1. A latch mechanism comprising, a hook-handle assembly including a hookmember, a handle, and a linkage arrangement coupled between the hookmember and handle, the handle adapted to control motion of the hookmember when unlocking and locking the latch mechanism; a clevis having ahook-end receiver and a coupler portion spaced apart from the hook-endreceiver to at least partially define an opening therebetween, thehook-end receiver configured to engage with a hook end of the hookmember as the handle moves from an open position toward a closedposition; a clevis-sensing lock carried on the handle, theclevis-sensing lock including a block coupled to the handle, a lockmember received in the block a tumbler arrangement coupled between thelock member and the block and configured to control movement of the lockmember relative to the block, and an interference member coupled to thelock member, the interference member configured to pass through theopening of the clevis in an unlocked position and engage an underside ofthe clevis to block movement of the handle relative to the clevis in alocked position, the lock member configured to control movement of theinterference member; and a device having a head, a shaft coupled to thehead, and a protrusion extending outward from the shaft, the shaftconfigured to be received in the lock member to engage with the tumblerarrangement to allow movement of the lock member, the protrusionconfigured to engage with the handle to trap the shaft within the lockmember when the lock member is in the unlocked position, and the headconfigured to extend away from the handle to provide an indication of anunlocked state of the clevis-sensing lock; wherein the clevis isconfigured to receive at least the interference member carried on theclevis-sensing lock and to allow movement of the lock member to thelocked position when the interference member is received through theclevis.
 2. (canceled)
 3. The latch mechanism of claim 1, wherein thetumbler arrangement includes a detent spring, a detent pin positionedbetween the lock member and the detent spring, and a tumbler pinpositioned between the detent pin and the lock member, wherein thedetent spring is configured to bias the detent pin toward the tumblerpin, and wherein the detent pin is configured to engage with the blockand the lock member to restrict movement of the lock member when aninterface between the detent pin and the tumbler pin is misaligned froma lower surface of the lock member.
 4. The latch mechanism of claim 3,wherein the device is further configured to engage with the tumbler pinand to align the interface between the detent pin and the tumbler pinwith the lower surface of the lock member when the device is received inthe lock member. 5-6. (canceled)
 7. The latch mechanism of claim 1,wherein the lock member is formed to include an annular groove and anaxial slot extending toward the interference member from the annulargroove.
 8. The latch mechanism of claim 7, further comprising across-pin configured to slide in the annular groove and axial slot ofthe lock member to control movement of the lock member.
 9. The latchmechanism of claim 8, wherein the clevis further includes a finextending from an upper surface of the clevis opposite the underside,and wherein the fin is configured to move the cross-pin out of the axialslot and into the annular groove to allow movement of the lock member asthe handle moves toward the closed position.
 10. The latch mechanism ofclaim 1, wherein the lock member is formed to include a groove extendingat least partially around a circumference of the lock member, andwherein a fastener extends through the handle and the block to couplethe clevis-sensing lock to the handle and is received in the groove ofthe lock member.
 11. The latch mechanism of claim 10, wherein the grooveof the lock member is configured to limit movement of the lock memberrelative to the block.
 12. A method of operating a latch mechanism, themethod comprising, inserting a device into a clevis-sensing lock throughan aperture formed in a handle of a hook-handle assembly; moving thedevice to disengage an interference member of the clevis-sensing lockfrom a clevis; moving the handle relative to the clevis to disengage afin of the clevis from the clevis-sensing lock to engage a cross-pin ofthe clevis-sensing lock with a lock member of the clevis-sensing lock toblock movement of the device such that the device is trapped in theclevis-sensing lock; and moving the handle to disengage a hook member ofthe hook-handle assembly from the clevis.
 13. The method of claim 12,further comprising, moving the handle toward the clevis to engage thehook member with the clevis; moving the handle toward the clevis toengage the fin with the clevis-sensing lock to disengage the cross-pinfrom the lock member to allow movement of the device; moving the devicesuch that the interference member is engaged with an underside of theclevis; and removing the device from the clevis sensing lock.
 14. Themethod of claim 13, wherein inserting the device comprises extending ashaft of the device into the lock member and engaging a tumblerarrangement to allow movement of the interference member.
 15. The methodof claim 13, wherein removing the device comprises removing the shaftfrom the lock member and disengaging the tumbler arrangement to blockmovement of the interference member.
 16. A clevis-sensing lockcomprising a block formed to include a first bore extending into theblock and a pin-receiving slot extending into the block to intersectwith the first bore; a lock member configured to be received in thefirst bore of the block and move relative to the block, the lock memberincluding a first end and a second end spaced apart from the first end,the lock member formed to include an annular groove, an axial slotextending toward the first end of the lock member from the annulargroove, and a second bore extending from the second end toward the firstend; a cross-pin positioned within the pin-receiving slot of the blockand configured to slide in the annular groove and axial slot of the lockmember to control movement of the lock member; a tumbler arrangementcoupled between the lock member and the block and configured to controlmovement of the lock member; a coupler shaft positioned within the keyreceiving second bore and coupled with the lock member to movetherewith; and an interference member coupled to the coupler shaft atthe first end of the lock member to move with the lock member.
 17. Theclevis-sensing lock of claim 16, further comprising a guide pin having ahead and a hole extending through the head, wherein the block is formedto include a cavity configured to receive the guide pin, and wherein thecross-pin extends through the hole of the guide pin.
 18. Theclevis-sensing lock of claim 17, wherein the tumbler arrangementincludes a detent spring, a detent pin positioned between the lockmember and the detent spring, and a tumbler pin positioned between thedetent pin and the lock member, wherein the detent spring is configuredto bias the detent pin toward the tumbler pin, and wherein the detentpin is configured to engage with the block and the lock member torestrict movement of the lock member when an interface between thedetent pin and the tumbler pin is misaligned from a lower surface of thelock member.
 19. The clevis-sensing lock of claim 18, further comprisinga fastener extending through the block, wherein the lock member isformed to include a groove extending at least partially around acircumference of the lock member, wherein the fastener is received inthe groove of the lock member, and wherein the groove of the lock memberis configured to limit movement of the lock member relative to theblock.
 20. The latch mechanism of claim 1, further comprising anindicator coupled to the device and configured to enhance the visibilityof the device and provide a signal to a user that the clevis-sensinglock is in the unlocked position.